Enlarge ImageRequest to buy this photoMike GROLL | ASSOCIATED PRESSJason Dufner, who won the PGA Championship at Oak Hill last year, autographs items on the eighth hole during a practice round at Valhalla Golf Club.

Enlisted to make a celebrity appearance during a gala charity announcement on the eve of last week’s Bridgestone Invitational in Akron, Jason Dufner appeared to have put the most trying part behind him when he stepped away from the microphone after delivering a brief speech.

All that remained for Dufner to do was hit a few putts with two former hospital patients, one in college and the other in grade school.

“I’m going to pass,” he said.

Known for his dry sense of humor, Dufner was not kidding. His reign as the PGA Championship titleholder has ameliorated his social anxiety, giving him a voice he has enjoyed exercising. But on the greens, his angst has worsened.

Asked why he did not want to putt during the ceremony, Dufner said, “I don’t really want to get beat by a kid.”

Winning has a way of framing rough edges in a downy light, so Dufner’s two-stroke victory last year over Jim Furyk at Oak Hill Country Club is remembered for his superlative iron play and not for his shaky putting — the tap-in putt for a second-round 63 that Dufner nearly missed; the 2-footer for par in the third round that rolled around the cup and dropped in; or the 1-footer in the final round that curled in.

Keegan Bradley, who beat Dufner in a playoff in the 2011 PGA Championship, said he would play with Dufner anytime, anywhere, so pure is the pleasure of observing Dufner’s game up close.

“His chipping, pitching, driving, irons — everything is as good as anybody out here,” Bradley said.

And his putting?

“I look away when he has the putter in his hand,” Bradley said. “I watch everything until he gets on the green, and then I’m done.”

At the start of the Bridgestone Invitational, Dufner ranked 170th on the PGA Tour in strokes gained putting. Two years ago, when he won his first two tour titles, he ranked 80th. In 2013, he was tied for 142nd.

In the first five months of 2013, Dufner did not record a top-10 finish, which few people remember because of how well he played in the next five. In June, Dufner tied for fourth at the U.S. Open, in August he tied for fourth at Bridgestone and won the PGA Championship, and in September he twice tied for ninth, in a FedEx Cup playoff event and at the Tour Championship.

“Had an average year last year till that major,” Dufner said, referring to the PGA. “Maybe it will be the same this year.”

He comes into the year’s final major, at Valhalla Golf Club in Louisville, Ky., under different — and difficult — circumstances. He is hampered by two bulging disks in his neck, which Dufner said he has struggled with since the Masters, where he missed the cut. After finally receiving a diagnosis two weeks ago, Dufner said he was treating the inflammation with steroid shots in the hope of avoiding surgery.

“So I’m kind of dealing with that and trying to get healthy,” he said.

It has been a trial. The night after Dufner’s first round at the U.S. Open, he did not sleep because of the discomfort. The next day, he chased his opening 72 with a 74 to miss the cut. (He tied for 51st at the British Open.)

“I can’t tell you the last day I put in a practice,” he said.

Dufner, 37, described trying to compete against the best in the world under such circumstances as challenging and impossible.

“Lack of sleep, lack of range of motion, lack of strength; there’s a lot of different issues when you’re dealing with your neck,” he said.

Dufner’s roots are in Cleveland, but his refuge is Auburn, Ala., where he and his wife, Amanda, own 50 acres. At Oak Hill last year, Amanda collected acorns as she walked outside the ropes. By the week’s end, she had collected more than four dozen, which the Dufners cultivated in planters upon returning home.

Dufner regards Auburn University, where he played on the golf team and earned his economics degree in 2000, as the planter and the people he met there as the gardeners who cultivated his gifts as a student and a player.

As a freshman, Dufner competed as a nonscholarship player. His rise from walk-on to major winner is a story he returns to campus regularly to share with athletes from various sports. Dufner has a great affinity for the football team, whose coach, Gus Malzahn, he regards as a kindred spirit.

Dufner got to know Malzahn, 48, after he became Auburn’s offensive coordinator in 2009. Like Dufner, Malzahn is a soft-spoken, hardworking man who seeks innovation and improvement over attention and acclaim. He conscripted Dufner to deliver a pregame speech to Auburn before last season’s game at Texas A&M, which the Tigers won 45-41 to help launch their appearance in the national-championship game.

“He’s as honest as they come,” Malzahn said. “He doesn’t say a lot, but when he does talk, it comes from the heart.”

Dufner is fascinated by the team dynamic, which makes football so different from golf. He also has a comfort level around athletes that he is slowly developing in less familiar environments. What Dufner learned from winning the PGA, he said, is that his success in golf has given him the superpower of visibility, with people more apt to pay attention to causes he chooses to champion, even if he has not been a winner lately.

“It created a self-awareness about my reach in different areas,” Dufner said. “It gives you a platform, it gives you a voice, so to speak. I think in the last six, eight months, that has really dawned on me that I could make a difference outside of golf in different things because of golf.”